Debugging a Build — The two files a debugger reads — --sld for source lines and -e for exported symbols — what is in each, and how the 0x1DE extension drives an assemble-and-run cycle under Bizmuth.
How Assembly Works — Gather, decide, emit — and why nearly every surprising behaviour is one of the three showing through: which names may be used before they are defined, where a MODULE body really lands, and why some warnings name a line long after you wrote it.
Diagnostics — How to read a message, what the level and the code mean, which warnings you have to ask for, the ones you will actually meet, the reserved words that cause the most confusing failures, and a table of every code FantASM can print.